Why does Europe need to increase its defense spending?

Europe has spent decades relying on the United States for defense while allocating its own resources to social welfare, creating what President Obama termed 'free riders.' This imbalance has been highlighted by multiple U.S. administrations, with Trump being particularly vocal about it. European nations need to develop a more autonomous defense approach to avoid being caught in bureaucracy and reduce their dependence on the U.S. While increased spending is necessary, Europe should be proactive but not fall into excessive pessimism about the future of transatlantic security relationships.